Clam cleat from Sea-Dog is manufactured from marine-grade nylon for ultimate durability in marine environments. Cleat is ideal for most applications where high loads or rope surges are not likely to be encountered. Corrosion-resistant design. For use with 3/8" - 5/8" rope. Uses 5/16" fasteners. 4-13/16"L x 1-7/16"W. 3-3/4" in between mounting holes.